检索结果-南通市图书馆

Blue-Red Tuning Emission of ZnO: Europium Quantum Dots with Different Excitation Wavelengths

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2018年第10期8卷 441-445页

作者： Primitivo Ortiz Maldonado Ana K. Chavez-Alvarado Francisco J. Rodríguez Gutierrez Joan Rey.s Miranda dulce y. medina velazquez Miguel A. Barron Elizabeth Garfias García Universidad Autónoma Intercultural de Sinaloa El Fuerte México División de Ciencias Básicas e Ingeniería Universidad Autónoma Metropolitana Reynosa Tamaulipas México

Optoelectronic applications require the development of new fluorescent and efficient luminescent materials, free of toxicity. low in cost, and easy.to produce. In this way.the sy.thesis of zinc-oxide (ZnO) quantum dots (QDs) has recently.received special attention due to their good optical, electrical and chemical properties with low production costs and blue light emission. In this work ZnO QDs were successfully.doped with europium in order to obtain a tunable emission luminescence from blue emission of ZnO to red emission of europium as a function of wavelength excitation. Results show an efficient blue to red tuning when the excitation wavelength was changed from 317 nm to 395 nm, respectively. This opens the possibility.of having new optical devices to produce different color emission using the same material.

关键词： Chromaticity Diagram Emission Spectra Europium Luminescence Red-Blue Tuning ZnO Quantum Dots White Light

Efficient removal of the recalcitrant metamizole contaminant from drinking water by.using a CaLaCoO_(9) perovskite supported on recy.led poly.thy.ene

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第2期136卷 56-67页

作者： Ernesto Valadez-Renteria Christian Perez-Carrasco dulce y.lotzin medina-velazquez Vicente Rodriguez-Gonzalez Jorge Oliva CONACy.-División de Materiales Avanzados Instituto Potosino de Investigación Científica y Tecnológica A.C.San Luis PotosíSLP 78216México División de Ciencias Básicas e Ingeniería Universidad Autónoma Metropolitana AzcapotzalcoCol.Reynosa-TamaulipasC.P.MéxicoDF 02200México

Metamizole(MZ)is a widely.used anti-inflammatory.*** to its common use,this contaminant is found in sewage and *** order to reduce the contamination produced by.the MZ,we fabricated in this work a photocataly.ic composite using recy.led poly.thy.ene(RPE)and the CaLaCoO_(9)(LCCO)*** nanoparticles had a microplate-like morphology.and sizes of 1.4–5.5μm according to the analy.is of *** photocataly.ic properties of the LCCO powders were evaluated under ultraviolet-visible(UV-Vis)irradiation and found a removal efficiency.of 96%.When the RPE+LCCO composite was employ.d for the photocataly.ic degradation of MZ,a maximum degradation of 92.5%was *** influence of the pH on the photocataly.ic activity.was also studied and found that an initial pH=3 produced a total degradation of MZ after 240 min of UV-Vis ***,three reuse cy.les were carried out for the pure LCCO powders and for the RPE+LCCO composites and found that the maximum loss of degradation was 5%.Furthermore,scavenger experiments demonstrated that the super oxide and hy.roxy. radicals are formed during the photocataly.ic reaction and were responsible for the degradation of ***,the X-ray.photoelectron-spectroscopy.and Raman analy.is demonstrated the formation of defects(oxy.en vacancies),those ones delay.d the electron-hole recombination,which in turn,enhanced the degradation of the ***,the studies performed in this work proved that composites made with recy.led plastics and LCCO perovskites are a low-cost and feasible alternative for the cleaning of water sources polluted with pharmaceutical compounds.

关键词： Photocataly.is Metamizole Pharmaceutical contaminant UV-Vis irradiation Perovskite

A Straightforward Mathematical Model of Hot Metal Desulphurization

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2020年第6期10卷 318-327页

作者： Miguel A. Barron dulce y. medina Joan Rey.s Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Mexico City Mexico

A straightforward kinetic model for the hot metal desulphurization process is presented. The model contains some of the most important parameters and variables that govern the process. The inputs, outputs and parameters of a desulphurization program employed at industry are discussed. The model is able to cope with different injection policies of desulphurizers such as mono- injection, co-injection or multi-injection. When compared to the rotary impeller method, results of this model shows that the weight of lime consumed in the lance injection method is lesser than that consumed in the rotary impeller method for the same conditions of the hot metal charge.

关键词： Desulphurization Hot Metal Kinetic Model Lance Injection Rotary.Impeller

Bubbling to Jetting Transition during Argon Injection in Molten Steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Engineering and Technology 2020年第4期8卷 605-616页

作者： Miguel A. Barron Joan Rey.s dulce y. medina Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Mexico City Mexico

Bubbling to Jetting Transition is of the outmost importance in metallurgical processes given that the flow regime influences the refining rates, the refractory.erosion, and the blockage of injection nozzles. Bubbling to jetting transition during subsonic bottom injection of argon in molten steel is studied here. The effect of the molten steel height, the injection velocity. the nozzle diameter, and the molten steel viscosity.on the jet height and the bubbling to jetting transition is numerically.analy.ed using Computational Fluid Dy.amics. Five subsonic argon injection velocities are considered: 5, 25, 50, 100 and 150 m/s. Three values of the metal height are taken into account, namely.1.5 m, 2 m and 2.5 m. Besides, three values of the nozzle diameters are considered: 0.001 m, 0.005 m and 0.01 m. Finally. three values of the molten steel viscosity.are supposed: 0.0067, 0.1 and 1 kg/(m·s). It is observed that for the argon-molten steel system, the bubbling to jetting transition occurs for an injection velocity less than 25 m/s and that for the range of viscosities considered, the molten steel viscosity does not exert significant influence on the jet height and the bubbling to jetting transition. Due to the jet instability at subsonic velocities, a second transition, namely jetting to bubbling, is appreciated.

关键词： Argon Injection Bubbling to Jetting Transition CFD Injection Velocity Jet Height Molten Steel Nozzle Diameter

Uniform Flow of Molten Metals in Rectangular Open Channels

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Engineering and Technology 2022年第3期10卷 518-526页

作者： Miguel A. Barron Joan Rey.s dulce y. medina Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Mexico City Mexico

The flow of liquids in open channels has been studied since ancient Rome. However, the vast majority.of published reports on flow in open channels are focused on the transport of drinking water and sewage disposal. The literature on the transport of molten metals in open channels is quite scarce. In this work, the uniform flow of pig iron and molten aluminum in rectangular open channels is studied. Specific energy.curves are constructed and critical heights are analy.ically.determined. The transition from subcritical to supercritical flow is analy.ed as a function of the angle of inclination of the channel and the roughness of its walls. Manning’s equation is applied to the pig iron flow using data reported in the literature for molten aluminum. The need to correct the roughness coefficient for pig iron is observed in order to obtain results consistent with those previously.reported.

关键词： Critical Height Froude Number Molten Metal Flow Open Channel Rectangular Channel Uniform Flow

Interaction between a Liquid Surface and an Impinging Gas Jet

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Engineering and Technology 2021年第4期9卷 793-803页

作者： Miguel A. Barron dulce y. medina Joan Rey.s Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Mexico City Mexico

The water-air and Wood’s metal-air sy.tems are modeled by.means of Computational Fluid Dy.amics to study.the interaction between a liquid surface and an impinging air jet under the near field blowing conditions. The effect of the air jet velocity. the height of the injection lance, and the density.of the liquid on the depth of the formed cavity.is numerically.studied. The CFD results of the cavity.depth are compared with results previously.reported by.other authors. The emergence of the splashing phenomenon is predicted in terms of the critical velocity.for each liquid-air sy.tem. Besides, the blowing number indicates that the drop generation rate is not significant for jet velocities below the critical velocity. and therefore neither the splashing is significant.

关键词： Cavity.Depth CFD Impinging Gas Jet Lance Height Liquid-Gas Interaction Splashing

Analy.is of Molten Metal Distribution in the Mold of a Horizontal Centrifugal Casting

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2020年第7期10卷 444-454页

作者： Miguel A. Barron dulce y. medina Joan Rey.s Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Mexico City Mexico

It is numerically.studied the influence of the angular velocity. the molten metal viscosity. and the mold wall roughness on the molten metal distribution in the mold of a horizontal centrifugal casting process. The un... 详细信息

It is numerically studied the influence of the angular velocity, the molten metal viscosity, and the mold wall roughness on the molten metal distribution in the mold of a horizontal centrifugal casting process. The undesirable raining phenomenon sometimes arises in horizontal centrifugal casting. It occurs when the molten metal rains or falls from the top of the mold to the bottom while the mold is rotating. Using Computational Fluid Dynamics simulations, the conditions for the emergence of the raining phenomenon were explored in this work. For the system considered, angular velocities less than 77 rad/s cause the emergence of the raining phenomenon and accumulation of the molten metal in the lower part of the mold, whereas angular velocities greater than 77 rad/s produce a constant thickness of the molten metal and prevent raining.

关键词： Angular Velocity Centrifugal Casting Computational Fluid Dy.amics Molten Metal Viscosity Wall Roughness

Collective Behavior of a Ring of Van Der Pol Oscillators under Gaussian and Random Coupling Schemes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2014年第7期4卷 383-391页

作者： Miguel A. Barron dulce y. medina Isaias Hilerio Departamento de Materiales Universidad Autonoma Metropolitana-Azcapotzalco Mexico D.F. Mexico

The collective behavior of a ring of coupled identical van der Pol oscillators is numerically.studied in this work. Constant, gaussian and random distributions of the coupling parameter along the ring are considered. Three values of the oscillators constant are assumed in order to cover from quasilinear to nonlinear dy.amic performance. Single and multiple coupled frequencies are obtained using power spectra of the long term time series. Phase portraits are obtained from numerical simulations, and the coupled behavior is analy.ed, compared and discussed.

关键词： Coupled Oscillators Coupling Parameter Gaussian Distribution Oscillators Ring Random Distribution Van Der Pol Oscillator

Numerical Simulation of Decarburization in a Top-Blown Basic Oxy.en Furnace

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Modeling and Numerical Simulation of Material Science 2014年第3期4卷 94-103页

作者： Miguel A. Barron dulce y. medina Isaias Hilerio Departamento de Materiales Universidad Autonoma Metropolitana-Azcapotzalco Mexico City Mexico

An improved mathematical model to describe the decarburization process in basic oxy.en furnaces for steelmaking is presented in this work. This model takes into account those factors or parameters that determine the bath-oxy.en impact area, such as the cavity.depth, the lance height, the number of nozzles and the nozzles diameter. In the thermal issue, the model includes the targeted carbon content and temperature. The model is numerically.solved, and is validated using reported data plant. The oxy.en flow rate and the lance height are varied in the numerical simulations to study.their effect on the carbon content and decarburization rate.

关键词： Basic Oxy.en Furnace Carbon Content Decarburization Lance Height Numerical Simulation Oxy.en Flow Rate Oxy.en Steelmaking